1. Field of the Invention
The present invention relates to a bottom structure for a bed which can be bent to a proper curvature while allowing a patient to continue feeling relaxed even though the bottom is being partially lifted.
2. Description of Related Art
Many of recent beds are equipped with a bottom lifting mechanism and various mechanisms are available. An ordinary liftable bed has a back bottom portion simply connected to a waist bottom portion. The waist bottom portion is simply connected to a leg bottom portion. When the back bottom portion is lifted, the joint between the back and waist portions acts as a pivot, (i.e. forming an actual fulcrum), while when the leg portion is lifted, the joint between the waist and leg bottom portions also acts as a pivot.
Therefore, as the back bottom portion is lifted up forming an angle, the angular space between the back and waist bottom portions near the joint is narrowed, and unless the angle fits the body of the patient in the bed, the waist, abdomen, and underside of the patient's legs are uncomfortably pressed by the mattress.